DiskMon

DiskMon

A sysops toolkit for scanning, monitoring, reporting, alerting, tracking top usage, checking health, fixing issues, cleaning up, backing up, restoring, logging, benchmarking, and comparing disk-related operations — all from the command line with full history tracking.

Commands

Each data command (scan, monitor, report, etc.) works in two modes:

• With arguments: Logs the input with a timestamp and saves to the corresponding .log file
• Without arguments: Displays the 20 most recent entries from that command's log

Data Storage

All data is stored locally in ~/.local/share/diskmon/. Each command writes to its own log file (e.g., scan.log, monitor.log, alert.log). A unified history.log tracks all activity across commands with timestamps.

• Log format: YYYY-MM-DD HH:MM|<input>
• History format: MM-DD HH:MM <command>: <input>
• No external database or network access required

Requirements

• Bash 4+ (uses set -euo pipefail)
• Standard POSIX utilities: date, wc, du, head, tail, grep, basename, cat
• No root privileges needed
• No API keys or external dependencies

When to Use

1. Tracking disk space trends over time — Use diskmon monitor and diskmon usage to log periodic disk space readings across servers, building a historical record you can search and export
2. Setting up alert documentation — Use diskmon alert to record threshold breaches and disk-full warnings, creating a searchable incident history
3. Documenting cleanup and maintenance — Use diskmon cleanup and diskmon fix to keep timestamped logs of what was cleaned, freed, or repaired on which systems
4. Benchmarking storage performance — Use diskmon benchmark and diskmon compare to log I/O test results and compare performance across different disks or configurations
5. Generating audit-ready exports — Use diskmon export json to produce a structured file of all logged monitoring activity for capacity planning, compliance reviews, or team handoff

Examples

Log a scan and review history

# Record a scan result
diskmon scan "/dev/sda1: 78% used, 45GB free"

# View recent scan entries
diskmon scan

Monitor, alert, and report workflow

# Log a monitoring observation
diskmon monitor "web-server-01 /var at 91% — nearing threshold"

# Log an alert
diskmon alert "CRITICAL: /data at 98% on prod-db-02"

# Generate a report entry
diskmon report "Weekly disk report: 3 servers above 85% threshold"

# Search across all entries
diskmon search "prod-db"

Cleanup and fix tracking

# Log a cleanup action
diskmon cleanup "Purged 15GB of old logs from /var/log on app-server-03"

# Log a fix
diskmon fix "Extended /home LVM volume by 20GB on dev-server"

# View recent activity
diskmon recent

Export and statistics

# Summary stats across all log files
diskmon stats

# Export everything as JSON
diskmon export json

# Export as CSV for spreadsheet analysis
diskmon export csv

# Health check
diskmon status

Backup, restore, and benchmark

# Log a backup
diskmon backup "Snapshot of /data volume taken at 03:00 UTC"

# Log a restore test
diskmon restore "Verified restore of /etc from snapshot-2025-03-15"

# Log a benchmark result
diskmon benchmark "Sequential write: 480 MB/s on /dev/nvme0n1"

# Compare two benchmark runs
diskmon compare "nvme0n1 vs sda: 480 MB/s vs 210 MB/s sequential write"

How It Works

DiskMon uses a simple case-dispatch architecture in a single Bash script. Each command maps to a log file under ~/.local/share/diskmon/. When called with arguments, the input is appended with a timestamp. When called without arguments, the last 20 lines of that log are displayed. The stats command aggregates entry counts across all logs, export serializes everything into JSON, CSV, or plain text, and search greps across all log files for a given term.

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